Automatic door closer



July 23, 1963 BOMM ET AL 3,098,259

AUTOMATIC DOOR CLOSER Filed OG'. 4, 1960 im wm i l l.-

/NVENTOPS M1, 6M

KW geval-W Y IM' e 29W@- United States Patent O 3,098,259 AUTOMATIC DOOR CLOSER Heinz Bumm, Ennepetal-Voerde, and Klaus Berghaus, Voimarstein (Ruhr), Germany, assignors to Dorken & Mankel KAG., Ennepetal-Voerde, Germany, a firm Filed Oct. 4, 1950, Ser. No. 60,492 Claims priority, application Germany Get. 16, 1959 3 Claims. (Cl. 16-59) This invention relates to door closers, and more specifically to an automatic door closer with a casing enclosing a damping cylinder, which is provided with a recess at least partially projecting into the cross-section of the damping cylinder and adapted to receive a fiat spiral spring which loads a shaft supported by a bearing neck projecting into the recess. Such automatic door closers can be manufactured with relatively small external dimensions which, however, often `do not yet meet satisfactorily tall lpractical requirements. Using the conventional forms of construction, a further reduction of the dimensions can scarcely be obtained because, in the known forms of construction, the lbearing neck substantially supporting the shaft is formed of a separately manufactured structural member which is screwed `onto the casing after the shaft has been fitted. This screw connection requires a relatively ylarge headroom which has a direct effect on the total height of the device.

An automatic Ydoor closer to -be arranged at the upper portion of a door is already known which has a cylindrical casing on which a bearing neck for a shaft is integrally formed. The bearing neck is embraced by a spring shaped as a iiat spi-ral spring which loads the shaft. However the spring is not accommodated in a recess of the casing but is located freely above the upper region thereof and can be covered by a cap. In this form of construction, the shaft must be inserte-d from the outer end of the bearing neck and is therefore detachably coupled with a separately manufactured eccentric forming a crank. For this purpose, either a tongue-and-groove connection or a square coupling region is provided. Such constructions have not proved successful -in practice because considerable peripheral -forces occur in the region of the detachable connection of the eccentric with the shaft and heavily stress the connection. The play necessarily to be provided for the connection because of the provided detachability increases rapidly due to the heavy stresses occurring in the operation. This decisively restricts the usability of the door closer. Further known is a loft door closer having a shaft which is loaded by a tension spring. In this case, the shaft of the door closer controls by means of two nonrotatably mounted cams a frame longitudinally shiftable rectilinearly which establishes the connection with a spring. In mounting the shaft with the structural members associated therewith, ie. the cams and the frame, they are inserted through a lower closable opening in the casing whereas, for establishing the connection of the frame with the spring, another opening is required in the upper part of the wall of the casing, which must likewise be closed. Such a door closer, however, possesses neither a damping cylinder nor a recess in the casing partly projecting into the crosssection of the cylinder, vfor receiving a iiat spiral spring. Furthermore, the aforementioned known door closer has no Abearing neck projecting into the recess and supporting the shaft of the closer, as the shaft is `guided in the upper region through a bearing eye which projects from the wall of the casing both upwardly and downwardly. Besides, the shaft does not cooperate with the spring by means of a crank drive.

It is the object of the invention to provide an automatic door closer of the kind described above, which is of simple construction and of smaller `dimensions as com- 3,098,259 Patented July 23, 1963 lCe pared lwith the known forms of construction and, consequently, can be manufactured at low costs and with improved reliability of operation.

The invention provides an automatic door closer which comprises in combination a casing, a damping cylinder enclosed by said casing, a recess at least partially projecting into the cross-section of said cylinder, for receiving a flat spiral spring, a bearing neck projecting into said recess and forming an undetachable part of said casing, a shaft supported by said bearing neck and loaded by said at spiral spring accommodated in said recess, a control means carried by said shaft and undetachably connected thereto, a connecting rod for said cont-rol means, a damping piston arranged to be controlled by said control means through said connecting rod, and a closable mounting aperture in said casing on the side remote from said bearing neck.

This combination of features results in a construction of the door closer which occupies very little space and is yet reliable in operation. It requires but few parts which can read-ily be manufactured and mounted and makes it possible considerably to reduce the dimensions, especially the headroom, as the bottom `of the recess receiving the spring and forming part of the wall of the casing need be only of small thickness, without in any way impairing the loading capacity. Moreover, the space containing the drive for the damping piston is easily accessible so that the mounting can be effected in a simple manner.

Various embodiments of the invention are possible. However, it is recommended to construct the crank integrally formed on the shaft of the door closer as an eccentric, as in this way considerable savings in headroom can be obtained over the cranks hitherto used, as a rule, in comparable closers and having crank webs and a crank-pin. Furthermore, it is possible to equip in a manner known per se the closure member for the mounting opening arranged in the bottom of the casing with a step bearing for the tend of the shaft directed towards it. This, however, is not absolutely necessary as the shaft can be so reliably guided without difliculty in the bear-ing neck integrally -forrned on the casing that here all -stresses are taken up. The closure member is preferably constructed as a screw plug which, on being mounted, adapts itself to the periphery of the casing.

A preferred rembodiment of the invention will now be described by way of example and with reference to the accompanying drawing, in which the only FIG- URE is a sectional view of an automatic `door closer according to the invention.

As shown in this figure, the automatic door closer includes a one-piece casing which substantially encloses a cylinder 5 lforming a damping device and having Ia piston `6 within it and is provided on its upper side with a recess 7 adapted to receive a flat spiral spring whose outline is lillustrated :by broken lines. A 4bearing neck -8 integrally formed on this casing projects into the recess 7 and supports a shaft 9. The cylinder 5 contains a damping Huid, such as oil. The piston 6 has a stepped longitudinal bore 19 in which a hall 20 is -arranged to operate as a ibackpressure valve which permits a working space 21 of lthe cylinder 5 to be lled with `a pressure lfluid Iwhcn the piston 6 returns. The working space 21 is connected by means of a passage (not shown) to the portion of the cylinder 5 in which the fluid is stored, the cross-section of this passage being adjustable. Such arrangements are known per se and, therefore, need not Ibe yfurther explained. 'Mounted on the outer end of the shaft 9 is a lever 10 which can be arrested in a known manner in its actual-ly expedient turning position and secured with the aid of a screw member 11. The portion of the shaft 9 projecting from the bearing neck 8 into the cylinder 5 carries an undetachably connected control means 12 which is shown 4in the drawing as an eccentric. This control means or eccentric 12 is Iarranged to drive the piston 6 through the intermediary of a straight connecting rod 13. However, for lfurther reducing the headroom, the connecting rod 13 may be bent upwardly along its length to permit the recess 7 adapted to receive the flat spiral springparticularly deeply to project into the cross-section of the cylinder, for the control means 12 can then be positioned below the centre line of the cylinder so that the headroom is further reduced. The free end of the cylinder 5 is closed in a manner known per se by means of a screw plug 14. Oppositely thereof, a screw plug 15 can be mounted in the casing. For mounting the shaft 9 with the control means 12, an aperture is provided in a lower wall 16 of the casing, which aperture can be closed by means of a screw plug 17 which may carry a step bearing for the shaft 9. However, such a -step bearing can, as a rule, be dispensed with. The screw plug 17 has an upper surface abutting against a bottom surface of the eccentric 12 for supporting the same and the shaft 9. A sleeve 18 is`rotatab1y mounted in a known manner on the outer shell surface of the bearing neck 8 and serves as a coupling member for the inner end of the tlat spiral spring accommodated in the recess 7. The sleeve `18 can be coupled with the lever 10 lin a known manner in selective turning positions. The outer end of the flat spiral spring can be secured in a known manner to the side wall of the recess 7.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of `the invention 4being indicated by the appended claims rather than by the foregoing description and all changes which come -within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. For example, the outer form of the casing may be modified in various Ways. The control means 12 may be positioned below the longitudinal axis of the cylinder S and may operate a bent connecting rod or a connecting rod eccentrically engaging the piston6.

We claim:

1. An automatic door closer comprising, in combination, a casing forming a damping cylinder at one end thereof and having in the region of the other end thereof a depressed portion providing a recess extending transverse to the cylinder below the uppermost portion thereof `for receiving a spiral spring, said casing having a bottom wall portion located opposite said recess and formed with an aperture, said bottom `wall potrion of said casing having a greater thickness ythan the opposite wall portion forming the bottom wall of said recess; a bearing neck projecting into said recess and being integrally formed with said casing; a shaft supported at an upper portion thereof by said bearing neck and adapted to be connected to a spiral spring located in said recess so as to be loaded thereby; an eccentric tixedly mounted on said shaft for rotation therewith; a damping piston slidably mounted in said damping cylinder; connecting means connecting said eccentric with said pitson so as to oscillate said piston during turning of said shaft; and bearing means having at least the same thickness as said bottom wall portion of said casing and closing said aperture and supporting said shaft and said eccentric, so that the distance between said eccentric .and said spring recess is smaller than the distance between said eccentric andthe bottom face of said bottom wall portion of said casing.

2. An automatic door closer comprising, in combination, a casing forming a damping cylinder at one end thereof and having in the region of the other end thereof a depressed portion providing a recess extending transverse tothe cylinder below the uppermost portion thereof for receiving a spiral spring, said casing having a bottom wall portion located opposite said recess and formed with an aperture, said bottom wall portion of said casing having a greater thickness than the opposite wall portion forming the bottom wall of said recess; a bearing neck projecting into said recess and being integrally formed with said casing; a shaft supported at an upper portion thereof by said bearing neck and adapted to be connected to a spiral spring located in said recess so as to be loaded thereby; an eccentric iixedly mounted on said shaft for rotation therewith; a damping piston slidably mounted in said damping cylinder; a substantially straight connecting rod connecting said eccentric with said piston so as .to oscillate said piston during turning of said shaft, said connecting rod having a center line substantially aligned with the center line of said piston and located in a plane of symmetry of said eccentric; and bearing means having at least the same thickness as said bottom wall portion of said casing and closing said aperture and supporting said shaft and said eccentric, so -that the distance between said eccentric and said spring recess is smaller than the distance between said eccentric and the bottom face of said bottom wall portion of said casing.

3. An automatic door closer comprising, in combination, a casing forming a damping cylinder at one end thereof and having in the region of the other end thereof a depressed portion providing a recess extending transverse to the cylinder below the uppermost portion thereof Ifor receiving a spiral spring, said casing being formed in a bottom wall portion thereof opposite said recess with an aperture provided with an inner screw thread, said bottom wall portion of said casing having a greater thickness than an `opposite wall portion which fforms the `bottom wall of said recess; a bearing neck projecting from said bottom wall of ysaid recess into the same and being integrally formed with said bottom wall of said recess; a shaft supported at an upper portion thereof by said bearing neck and adapted to be connected to a spiral spring located in said recess so as `to be loaded thereby; an eccentric fixedly mounted on a bottom portion of said shaft for rotation therewith; a damping piston slidably mounted in said damping cylinder; a substantially straight connecting rod connecting said eccentric with said piston so as to oscillate said piston during turning of said shaft, said connecting rod having a center line substantially aligned with the center line of said piston and located in a plane of symmetry of said eccentric; and a plug formed with an outer screw thread engaging said inner screw thread of said aperture Aand closing the latter, said plug having at least the same thickness as said bottom wall portion of said casing and having an upper surface abutting against a bottom surface of said eccentric for supporting the same and said shaft, so that the distance between said eccentric and said spring recess is smaller than the distance .between said eccentric and the bottom face of said bottom wall portion of said casing.

References Cited in the le of this patent 

1. AN AUTOMATIC DOOR CLOSER COMPRISING, IN COMBINATION, A CASING FORMING A DAMPING CYLINDER AT ONE END THEREOF AND HAVING IN THE REGION OF THE OTHER THEREOF A DEPRESSED PORTION PROVIDING A RECESS EXTENDING TRANSVERSE TO THE CYLINDER BELOW THE UPPERMOST PORTION THEREOF FOR RECEIVING A SPIRAL SPRING, SAID CASING HAVING A BOTTOM WALL PORTION LOCATED OPPOSITE SAID RECESS AND FORMED WITH AN APERTURE, SAID BOTTOM WALL PORTION OF SAID CASING HAVING A GREATER THICKNESS THAN THE OPPOSITE WALL PORTION FORMING THE BOTTOM WALL OF SAID RECESS; A BEARING NECK PROJECTING INTO SAID RECESS AND BEING INTEGRALLY FORMED WITH SAID CASING; A SHAFT SUPPORTED AT AN UPPER PORTION THEREOF BY SAID BEARING NECK AND ADAPTED TO BE CONNECTED TO A SPIRAL SPRING LOCATED IN SAID RECESS SO AS TO BE LOADED THEREBY; AN ECCENTRIC FIXEDLY MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH; A DAMPING PISTON SLIDABLY MOUNTED IN SAID DAMPING CYLINDER; CONNECTING MEANS CONNECTING SAID ECCENTRIC WITH SAID PISTON SO AS TO OSCILLATE SAID PISTON DURING TURNING OF SAID SHAFT; AND BEARING MEANS HAVING AT LEAST THE SAME THICKNESS AS SAID BOTTOM WALL PORTION OF SAID CASING AND CLOSING SAID APERTURE AND SUPPORTING SAID SHAFT AND SAID ECCENTRIC, SO THAT THE DISTANCE BETWEEN SAID ECCENTRIC AND SAID SPRING RECESS IS SMALLER THAN THE DISTANCE BETWEEN SAID ECCENTRIC AND THE BOTTOM FACE OF SAID BOTTOM WALL PORTION OF SAID CASING. 